Choke devices for use with shotguns are well known. The choke, when coupled to the barrel end of the shotgun, serves one of several purposes. It may restrict the shot pattern, or may result in a more disperse shot pattern, depending on the construction of the choke. Restricting shot pattern is generally achieved by decreasing the inner diameter of the choke approaching the muzzle end. It is known in this regard to use a series of annular steps to decrease the internal diameter of the choke. The decrease in diameter causes the shot to remain tightly compacted for a longer period of time, resulting in a tighter shot pattern. Conversely, by increasing the internal choke diameter approaching the muzzle, a more disperse shot pattern can be achieved. The actual degree of dispersion or restriction is determined by the shooter according to type of firearm and target being attempted.
Most often, the choke is used to restrict shot pattern. While annular grooves accomplish this to some degree, there remains a need for still further improvement. In addition, the wadding in which the shot is encased affects shot dispersion. As the wadding travels through the shotgun barrel toward the muzzle, including through an attached choke, the friction of the wadding on the muzzle interior slows the progress of the encased shot. It is known to use the decreasing diameter of annular grooves to retard the wadding in an attempt to release the shot more quickly. While the annular steps address the issue to some extent, there remains room for improvement.
An additional shotgun feature that affects gun performance is the build up of gas pressure behind the wad. It is this pressure that forces the wad through and out of the gun's barrel. However, it has been thought that this pressure can work against the desire to release the wad in such a manner that the shot pattern achieved is tight. This problem has been addressed thus far by providing apertures in the choke, or other means to expel the gas and pressure from the barrel of the gun and the choke mechanism. With devices such as these, the gas is released to the external environment surrounding the barrel, allowing the wad to proceed to the muzzle without experiencing further impact on the wad's compressed or uncompressed state.
Even with the addition of annular grooves and apertures to the choke mechanism, there remains a need for a device that further restricts or confines the shot pattern produced by a shotgun, particularly among those who target shot competitively, as well as among hunters in general.